It was, of course, all about Greece and the eurozone crisis, which will continue to dominate the summit before it winds up just after lunch today.

Yesterday evening, at a news conference, Nicolas Sarkozy, the French president and the conference host, expressed insisted that France and other countries were determined to defend the euro:

We cannot accept the explosion of the euro, which would mean the explosion of Europe. The problem must be posed in this fashion, and not otherwise.

If the euro is the core of Europe, the explosion of the euro would blow up Europe. And Europe is the guarantee of peace on the continent where people have behaved in the most brutal and violent manner of all continents of the world – not in the 15th century, but in the 20th century.

It is perfectly normal that two founding countries of Europe [France and Germany], and the two largest European economies, should take up the front line to defend a European heritage that has been bequeathed to us by our predecessors. The crisis of the euro is one of the most important crises that Europe has known since its creation.

Late last night, the US president, Barack Obama, met Sarkozy, Angela Merkel, the German chancellor, and officials from the EU and the IMF to discuss the eurozone crisis. The eurozone countries produced a rescue plan for Greece last week, but it is desperately short on detail and, if it is going to retain credibility with the markets, the G20 leaders need to be able to explain how it is going to be implemented.

In an interview on the Today programme a few minutes ago, the chancellor, George Osborne, said details of today's announcements were still being thrashed out. Unlike other G20 summits, this one was "not pre-cooked", he said.

It was a bad-tempered interview because Osborne repeatedly failed to answer questions about the extent to which Britain's contributions to the IMF may have to increase. Osborne criticised the BBC and other news organisations for suggesting that other countries were not also going to increase their lending to the IMF. All countries had a responsibility to protect the global economic system, he said.

The government will conclude agreement with us for a new agreement, the European Union and IMF programme, so I believe all the problems will be solved.

But Barroso also conceded that the option of Greece leaving the euro had been discussed. I'll post more comments from his interview later.

There is a series of working sessions at the summit this morning, followed by a working lunch. Sarkozy will wrap up the summit with a press conference at 1.15pm UK time (the timestamps on this blog are in French time), and David Cameron will give a press conference soon afterwards. I'll be covering all the G20 news, as well as bringing you the best comment from the internet, until the summit ends.

9.55am: Here are some more extracts from the interview that José Manuel Barroso, the European Commission president, gave to the Today programme.

I've taken the quotes from PoliticsHome.• Barroso said that he expected the Greeks to accept the austerity measures being demanded as the price for their bailout.

What is the other option for the Greek people? It is to have default and ot have real difficulty to pay their wages to the public servants to the schools to the hospital sit will be the paralysis of the country so I'm sure that the majority of the Greek people are reasonable people and they don't want this kind of chaos to come to their country.

• He confirmed that European leaders had discussed the possibility of Greece leaving the euro.

What I heard from [France and Germany] and from others is, in fact the possibility of a country that does not respect the commitments to leave the organisation to which it belongs, namely the euro, but, of course, it's a decision of the country itself, it's not a decision of the other countries.

• He said there would have to be closer fiscal union in the eurozone very soon.

We have a common currency amongst 17 countries but we have not yet created all the instruments that a common currency demands and it is true that is unfinished business. Until the financial crisis it was possible to live without those instruments but now we have been creating new instruments, for instance the European Financial Stability Facility and others.

Some of these changes may require a treaty change, he said.

10.11am: Italy is on the naughty step. According to Reuters, it has agreed to allow the IMF to monitor whether or not is implementing its austerity programme. It's a measure usually reserved for a country that is in trouble. Here's an extract from the Reuters story.

Italy, under fierce pressure from financial markets and European peers, has agreed to have the IMF and the EU monitor its progress with long delayed reforms of pensions, labor markets and privatization, senior EU sources said on Friday.

Prime Minister Silvio Berlusconi, his government close to collapse after more loyalists defected on Thursday, agreed to the step in late-night talks with euro zone leaders and U.S. President Barack Obama on the sidelines of a G20 summit in Cannes, France.

The Italian move came after Greece stepped back from a proposed referendum that could have triggered its exit from the euro area and agreed to seek national consensus in support of a 130 billion euro ($178 billion) new bailout program.

"We need to make sure there is credibility with Italy's targets -- that it is going to meet them. We decided to have the IMF involved on the monitoring, using their own methodology, and the Italians say they can live with that," one EU source said

10.16am: The G20 leaders are in a meeting now. The first few minutes were filmed, and the footage was shown in the press room, but there was no sound. Barack Obama and David Cameron seemed to be having a heated discussion. It wasn't a row, but there did seem to be rather a lot of firm hand-waving. At times like this you could do with a lip reader.

10.21am: Here's a summary of some of the overnight G20 news from the news wires.

• G20 leaders are reportedly discussing boosting the IMF's lending power by $250bn. As Reuters reports, the idea being discussed is to replicate a 2009 decision by G20 leaders that agreed to a special allocation of $250 billion of IMF Special Drawing Rights, the IMF's internal unit of account, to its 187 member countries. Some members could choose to sell part or all of their new SDR allocations to other members in exchange for hard currency, for example to meet balance of payments needs, while other members could buy more SDRs as a means of reallocating their reserves. One source from a large emerging market country said that if euro zone countries combined their SDR allocations, it could make available roughly $200 billion to Europe.

• China has firmly resisted calls to allow it currency to appreciate. As Aaron Back reports in a post on the Wall Street Journal's G20 blog, Hu Jintao, the Chinese president, said: "To keep asking emerging markets to revalue their currencies and reduce exports will not lead to balanced growth. On the contrary, it would only plunge the global economy into a 'balanced recession,' and make sustainable growth impossible." Back says that Chen Deming, the Chinese commerce minister, told reporters on the sidelines of the summit tha the yuan has already appreciated to a reasonable level. Chen said the yuan had risen around 30% against the U.S. dollar since 2005, and that China's external surpluses were declining as a percent of its gross domestic product.

• Russia has said that it is in the verge of joining the World Trade Organisation. President Dmitry Medvedev said that a trade deal it had agreed with Georgia would pave the way for it to be allowed into the trading bloc. According to one report, this will be "the biggest step in world trade liberalisation since China joined a decade ago, making its $1.9tr economy more attractive to investors 20 years after the collapse of the Soviet Union."• G20 leaders are going to toughen the rules governing the regulation of shadow banking. According to Reuters, they will call on the global securities regulator IOSCO to assess credit default swap markets and agree to strengthen oversight of shadow banking.They will also call on IOSCO and the Financial Stability Board to prepare 'too big to fail' rules for non-bank financial entities by the end of 2012.

• On Friday G20 leaders are signing what is described as a "convention on fighting tax evasion". It is the only convention that will be signed by all the G20 leaders at the Cannes summit. Martin Hearson, ActionAid's tax policy adviser, said: "The convention is a tool to help countries share information on taxpayers with each other. A number of countries will sign only letters of intent, but the collective endorsement is nonetheless a step forward on tax transparency."

The proliferation of bilateral deals with Switzerland, which leave secrecy intact, demonstrates that a global initiative on tax havens is necessary. However, ActionAid says there are reasons to question the effectiveness of the convention. It is based on standards set by the OECD on information exchange between the tax authorities of different countries, but the effectiveness of those standards is unclear.

• A 'blacklist' of uncooperative jurisdictions published at the 2009 London G20 summit was effectively updated in advance of the summit with a higher standard of compliance. Eleven jurisdictions have been included in 'black' and 'grey' lists, although the report will not describe them as such. President Sarkozy told NGOs on Wednesday that the fight against tax havens "will be no use without a [black]list."

ActionAid understands the current communiqué draft acknowledges for the first time the damaging effect on developing countries of tax havens and tax dodging by multinational companies. These are welcome words which need to be backed up with action by the G20.

• ActionAid understands that the current draft of the G20 communiqué will not take up the recommendation made by the Gates report as well as a report commissioned by the G20 from international organisations including the OECD, IMF and UN to force oil and mining companies to publish the payments they make to governments. This would be a missed opportunity.

The Prime Minister met Prime Minister Noda of Japan this morning. They discussed the global economy and agreed on the importance that the eurozone made progress on implementing the deal agreed last week. Prime Minister Noda welcomed the Prime Minister's report on Global Governance and said he looked forward to seeing the full report when it is discussed later this evening. They also agreed to build on the strong relationship between our two countries, particularly through trade, investment and defence co-operation. The Prime Minister expressed regret that his planned visit to Japan was postponed and said that he looked forward to rearranging his visit to Japan.

On Thursday, November 3, Prime Minister Yoshihiko Noda, who is visiting Cannes for the G20 Summit, held a meeting with the Rt Hon David Cameron MP, Prime Minister of the United Kingdom (UK), from 11:39 a.m. local time (7:39 p.m. Japan time) for around 20 minutes. The overview of the meeting is as follows (Attending on the Japanese side were: Mr. Jun Azumi, Minister of Finance; Mr. Hiroyuki Nagahama, Deputy Chief Cabinet Secretary; Mr. Hiranao Honda, Special Advisor to the Prime Minister; among others. Attending on the UK side were: Sir Jonathan Cunliffe, Europe and Global Issues Adviser; Sir Peter Ricketts, National Security Adviser; among others.).

There are five more paragraphs, covering all the subjects that came up. (I notice that Cameron tried to flog some Eurofighters.) As I said, it's not paticularly interesting. But it is very thorough.

11.12am:Brendan Barber, the TUC general secretary, is in Cannes as part of the L20, a group of trade union leaders invited by Nicolas Sarkozy to the summit alongside the B20 group of business chiefs. Barber held a press conference this morning. My colleague Larry Elliott was there and he sent me this.

Barber said the G20 would announce an employment task group with a particular focus on youth joblessness amid growing concern about the worsening outlook for global labour markets. G20 ministers will be be in charge of the task group with input from both business and unions.

"We have met 10 heads of government in the last 36 hours, including Barack Obama and David Cameron", Barber said. "Our main message is the need to put jobs up the agenda. Obama said he thought the emphasis should be put on jobs and growth rather than austerity. He was very positive about the labour movement having a strong voice and said that in some parts of the world the financial crisis was being used to attack labour rights."

11.24am: More on Italy. This is from Sam Fleming, the Times's economics editor, on Twitter.

Italy was pushed in the G20 talks to accept an IMF credit line but unsurprisingly rejected this; some sort of IMF monitoring more likely

The German political establishment sees Silvio Berlusconi as a catastrophic menace and perhaps the biggest single obstacle to world economic stability. They would dearly like him removed from the political picture and it will be interesting to see what phone calls there are between now and next week between senior European figures and Italian politicians to, how shall we put this, reconfigure Italian politics.

11.42am: Leparmentier Arnaud is a Le Monde journalist, and he thinks the summit could fail. He's just posted this on Twitter.

Il faut peut être le dire: #échec du #G20 est très possible

That translates as: It has to be said. Failure at the G20 is a real possibility.

11.53am: Arnaud isn't the only journalist being told that the summit could tank. We've just heard heard exactly the same message. The talks are an a "knife edge", we're told, and there is no guarantee that there are going to be any firm conclusions. There will be a communique, of course, but the issue is whether it contains specific measures to firm up the eurozone rescue plan or whether it is largely waffle. From what we can tell, it seems that the eurozone countries are coming under firm pressure to firm up the details of the Greek rescue package that they announced last week. (As is said earlier, it is woefully thin - as you can see for yourself, it only runs to seven paragraphs.) It looks as if the Americans and others are refusing to put money into the IMF unless the eurozone countries firm up their plans too.

There is often brinkmanship in the final moments of these summits, and it is probably too soon to sell all your shares and run for the hills yet, but a glittering success looks unlikely. Nicolas Sarkozy is due to give his press conference at 2.15pm. The markets will still be open. It will probably be up to them to deliver the final verdict.

12.49pm: On our eurozone debt crisis live blog, Graeme Wearden has put up a post from Tom Kington in Rome on a report that Italy was offered a €44bn 'precautionary' credit line by the IMF. The story, in Italian daily Corriere della Sera, is tied up with the news that the IMF is monitoring Italy's implementation of economic stimulus reforms.

The offer of a crutch, adds the paper, was turned down by Silvio Berlusconi, who was wary of the strings attached. With the European Central Bank already pushing Italy to liberalise its economy in return for buying government bonds, and Nicolas Sarkozy claiming at Cannes that it was not what reforms Italy is planning that counts as much as when they actually get put into effort, Berlusconi is already under huge pressure to push through his new stimulus package.

The package is now likely to be attached to a budget bill and put to a confidence vote in the Italian Senate on November 15.

Italian lawyers are already on war-footing over moves to include measures in the package to open up the legal profession to greater competition. La Stampa points out that around 150 lawyers sitting in parliament were instructed by their professional association to vote down similar measures when they were proposed by the government this summer.

Some are predicting Berlusconi's government could fail to muster a majority on November 15, although a procedural vote next Tuesday wrapping up the 2010 budget in the lower house may also see the government go under as Berlusconi loyalists desert him.

Supporters of the prime minister who have been with him since his early days have been notable for voicing dissent in recent days, likely because they have seen Berlusconi trying to shore up his government by handling plum roles to new adherents.

1.03pm: Angela Merkel, the German chancellor, has been speaking. She seems to have said the G20 failed to reach an agreement on putting extra money into the IMF.

"Hardly Any" G20 Countries Have Said They Will Participate In EFSF: Merkel

Reuters have just snapped this as a result.

EURO FALLS VS DOLLAR TO AROUND $1.3806 FROM $1.3830 AFTER MERKEL COMMENTS ON EFSF

1.29pm: This is from Reuters. It means traders are buying German bonds because they are selling other, riskier government debt.

German Bund futures rose on Friday after German Chancellor Angela Merkel said few countries In the Group of 20 leading economies had committed to participation in Europe's bailout fund.Euro zone leaders agreed on Oct. 26 to scale up the fund, the European Financial Stabilty Facility (EFSF), but gave no firm details of where the extra money would co from."Merkel said hardly any countries in the G20 had said they would participate in the EFSF. To me the EFSF is starting to look dead on arrival," a trader said.Greece remained a key focus for the market after it said it had dropped plans for a referendum on its euro membership before a confidence vote in its government and with investors cautious ahead of U.S. jobs data.

1.33pm: And here's another update from Reuters.

Shares and the euro lost ground on Friday after Germany's chancellor said very few leading nations had committed to supporting the euro zone's bailout fund, raising fresh concerns about the region's ability to tackle its debt crisis.Investors also stayed on edge ahead of U.S. monthly jobs data, due at 1230 GMT, with European shares shedding early gains and U.S. stock index futures (SPc1) (DJc1) (NDc1) down 0.1 to 0.3 percent, indicating a weak start for Wall Street.

1.37pm: More negative market reaction to the Merkel comments. This is from Reuters.

U.S. stock index futures extended losses after German Chancellor Angela Merkel said hardly any countries in the Group of 20 industrialized nations said they will participate in the euro zone bailout fund.

S&P 500 futures fell 6.7 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration of the contract. Dow Jones industrial average futures dropped 46 points while Nasdaq 100 futures lost 15.25 points.

c) Governments in the euro area commit to take all necessary measures and actions needed to ensure the stability of the euro area and have adopted a comprehensive package. (i) after having decided to flexibilise the EFSF instrument on the 21 July 2011, the 26 October euro area Summit agreed on a substantial leveraging of its resources up to 1 trillion euro. (ii) Euro area countries agreed to significantly strengthen economic and fiscal surveillance and governance of the euro area. (iii) A particular effort in terms of fiscal consolidation and structural reforms will be made by those euro area Member States that are experiencing tensions in sovereign debt markets. (iv) An exceptional solution was found to establish the sustainability of the Greek public debt through a rigorous adjustment programme and a voluntary nominal discount on Greek debt held by private investors.

As Kuenssberg says, this adds very little to the agreement reached at the Wednesday summit last week which, as I said earlier, was desperately thin. (Read it for yourself - it won't take long, because it's only seven paragraphs.)

This may be premature, but it is starting to look as though this summit has been a failure.

2.00pm: Here's a lunchtime summary.• Angela Merkel has dashed hopes that the G20 will produce a robust response to the eurozone crisis. She has reportedly said that "hardly any" G20 countries want to contribute more money to the European Financial Stability Facility - the fund that is supposed to be able to deploy up to €1tr to defend Italy if (as seems quite possible) it finds it impossible carry on borrowing money on the markets. She also seems to have said that no agreement has been reached on putting extra money into the IMF. The details are unclear at the moment - I haven't been able to find a clear account of what she said - but the markets have already reacted negatively. This summit was built up in advance as a make-or-break moment when a Greek rescue package would have to be firmed up. There now seems almost no chance of that happening.• Italy has agreed to let the IMF monitor how it is implementing its austerity programme. This is a humiliation for Silvio Berlusconi, the Italian prime minister, although EU officials have claimed that Italy asked for this support.

2.12pm: Nicolas Sarkozy, the French president, has just started his press conference. And David Cameron will be giving his own press conference shortly.

I've got to go to the room where Cameron is speaking. I'll file again soon.

2.29pm: I'm now in briefing room 5, waiting for David Cameron to come and give his press conference. The laptop internet connection is a bit sluggish, but I hope it will hold out.

Most of the journalists in the room are from the British delegation. There are times when a British prime minister attracts considerable interest on the world stage. But Cameron - at least today - is not in that category.

2.31pm: I'll post a proper summary of what Nicolas Sarkozy has been saying after his is over. But here's what I have gleaned from Twitter.

• Sarkozy claimed he made some progress on economic issues.

• He said he had made progress on the Robin Hood tax. South Africa and Russia are come round to the idea, he said. But he seems to have said Britain was blocking it.

2.35pm: David Cameron is starting now.

He says this is a very difficult time for the world economy. He knows people at home are "very worried" about their jobs.

His objective has been to help Britain weather the storm.

The international crisis has confirmed that the government has taken the right steps. Interest rates are lower than at any time since the war, even though Britain has higher debts than many other countries.

The biggest boost to the economy would be for the eurozone to sort out its problems.

Britain's view has been clear and "forcibly expressed".

Britain wants:

• A stronger bailout fund.

• Proper recapitalisation of the banks.

• A solution to the Greek budget crisis.

The primary responsibility for sorting out the eurozone lies with the eurozone countries.

Britain will not bail out the eurozone. And it does not want the IMF to fund a bailout either.

But Britain is willing to help the IMF take steps to help the world economy. The IMF has 53 rescue programmes, and only three of them are in the eurozone.

2.39pm: Cameron is still talking.

Trade imbalances are a problem, he says. At this summit China has indicated that it will allow more currency fluctation. That is good, he says.

At the summit G20 leaders have also affirmed their determination not to return to protectionism. That is good, he says.

Russia will be allowed into the World Trade Organisation. Cameron says he welcomes that.

On the Doha trade round, there has been a frank discusussion. Cameron says Sarkozy has accepted the approach recommended by Cameron and some other leaders a few weeks ago. As a result the trade talks will only be taken forward in areas where there is the prospect of success.

Cameron says his paper on changing the governance arrangements was accepted.

At the G20 the leaders took "some positive steps forward". But he is not going to pretend the problems have been fixed.

2.43pm: Cameron is taking questions now.

Q: What are the chances of Britain going into recession?

Cameron says some progress has been made. At the start of the summit it looked as though the world could go backwards. That has not happened.

Clearly this is having an effect on the British economy.

But Cameron says he does not make forecasts himself.

Q: What did you think of eurozone leaders trying to alter the government in a member state?

Cameron says Britain is not in the eurozone.

At the G20 countries outside the eurozone have said they will do their part, but they have not been able to substitute for the action that needs to be taken within the eurozone itsef.

2.45pm: More questions.

Q: If you have not got an agreement, why are you all going home?

Cameron says progress has been made. They have reached agreement in some areas.

Q: Is Germany to blame for the lack of progress?

Cameron says there are strong views within the eurozone about how it works. (The Germans do not want the European Central Bank to take responsibility for the European Financial Stability Facility - the fund that will protect countries like Italy.)

Q: Isn't it the case that there is no deal?

Cameron says there is a deal on the eurozone. It's the one agreed last week. But the details need to be finalised.

There is also an agreement on the IMF, he says. Countries agree what it should do.

Q: Why should British taxpayers support the IMF?

Cameron says he has protected British taxpayers. He has ensured Britain will not contribute to more eurozone bailouts.

It is in Britain's interests to support the IMF.

2.50pm: More questions.

Q: You seem to be saying eurozone taxpayers aren't doing enough. So why should British taxpayers contribute more?

Cameron says that is not his message. Resourcing the IMF is not a substitute for the eurozone dealing with its own problems.

2.52pm: Two questions from my colleague Patrick Wintour.

Q: Why was there no agreement on the IMF?

Cameron says the worst thing would be to "cook up" a number without being clear who is paying for what.

Q: Will there be a vote in the Commons on any future contribution to the IMF?

Cameron says there has already been a vote follow the last decision to increase Britain's contributions. That vote allowed for some "headroom". Any extra contribution would be within that headroom.

• Cameron says there will be no parliamentary vote on any decision to increase Britain's contributions to the IMF.

2.55pm: The next question comes from the Sun's Tom Newton Dunn. Cameron makes a sarcastic comment about a story in the paper today saying Cameron was staying in a £1,500-a-night hotel.

Next question.

Q: Why shouldn't British taxpayers contribute to a eurozone bailout?

Cameron says that's not the job of Britain. That's a job for the eurozone.

2.57pm: Next question.

Q: If Greece were to leave the euro, what would that mean for Britain?

Cameron says the eurozone crisis has been bad for Britain. The Greek crisis is one aspect of this. The Greeks have to decide what they want to do. They have to sort their problems out, or leave the euro. They can't just string it out.

If Greece were to leave, there would be bad effects, including for the UK.

There has to be "decisive action".

That's it. Cameron has finished.

3.16pm: That was gloomy. At one point Cameron says the eurozone crisis was having a "chilling effect" on the British economy. I'll post a full summary soon, as well as a summary of what other leaders have been saying, before I finally wrap up.

3.22pm: My colleague Graeme Wearden is looking at the market reaction to the G20 announcement - or non-announcement, to be more accurate - on his eurozone debt crisis live blog. The euro is down, shares are down and bond yields (the cost of government borrowing) are up.

The euro has been falling against the dollar ever since Angela Merkel admitted that leaders had not agreed a way to expand the International Monetary Fund's firepower, and then rush to the aid of the eurozone.

The single currency is now down around one cent, to a low of $1.3751.

The yield on ten-year Italian bonds has jumped, to a high of 6.385% (from a low of 6.185%). Anything over 6% is bad news.

The cheer has gone right out of the financial markets. Germany's main stock market index, the DAX, fell 2%.

Here are the two key passage relating to the eurozone economic crisis.

On avoiding contagion in the eurozone

Advanced economies commit to adopt policies to build confidence and support growth and implement clear, credible and specific measures to achieve fiscal consolidation. We welcome the decisions by European Leaders on October 26th, 2011 to restore debt sustainability in Greece, strengthen European banks, build firewalls to avoid contagion, and lay the foundations for robust economic governance reform in the Euro area and call for their swift implementation. We support the measures presented by Italy in the Euro Summit and the agreed detailed assessment and monitoring by the European Commission. In this context, we welcome Italy's decision to invite the IMF to carry out a public verification of its policy implementation on a quarterly basis.

This is significant because it confirms that no progress has been made at the G20 on firming up the credibility of the European Financial Stability Facility (supposedly worth €1tn) which is meant to be available to support eurozone countries that need to borrow. This is meant to be the "firewall" leaders have been talking about. At the moment it is looking more like a hay one than a concrete one.

On putting more money into the IMF

We will ensure the IMF continues to have resources to play its systemic role to the benefit of its whole membership, building on the substantial resources we have already mobilized since London in 2009. We stand ready to ensure additional resources could be mobilised in a timely manner and ask our finance ministers by their next meeting to work on deploying a range of various options including bilateral contributions to the IMF, SDRs, and voluntary contributions to an IMF special structure such as an administered account. We will expeditiously implement in full the 2010 quota and governance reform of the IMF.

This means any decision about putting more money into the IMF has been postponed.

The Sun article was not supposed to be embarrassing to Cameron. It says that while Nicolas Sarkozy's hotel suite costs £32,000 a night, Cameron's only cost £1,680.

3.58pm: David Cameron did not try to put much of a gloss on the summit outcome at his news conference. He was about as gloomy as it is possible to be at one of these occasions without breaching diplomatic protocol.

David Cameron. Photograph: Toby Melville/REUTERS

Here are the main points from what he said.• Cameron admitted that the G20 summit had failed to resolve the eurozone debt crisis. The G20 leaders had taken some "positive steps forward", he said. But he went on:

The world has shown it is ready to act but I'm not going to pretend all of the problems in the eurozone have been fixed, they haven't.

• He said the crisis was having a "chilling effect" on the British economy.

It is in Britain's interest that the eurozone crisis is sorted out as rapidly as possible. It is having a chilling effect on our economy and for every day it goes on not resolved, it is a day that is not good for our economy. That is fact.

Asked if Britain would go into a recession again, he said that he was not an economic forecaster. The Office for Budget Responsibility would be revising its forecasts at the end of this month, at the time of the autumn statement. He sounded as if he is expecting it to deliver bad news.

• He revealed that if Britain does agree to lend extra money to the IMF, there will not be vote. That's because parliament has already voted to allow this. Cameron explained: "If you go back to our last increase in IMF resources there was a parliamentary vote. That vote allowed for some extra head room. That's what we would anticipate, using that head room."

• He said Greece had to take a firm decision about its future and not "string this out endlessly".

The Greeks have to decide. Do they want to stay in the eurozone, accept the debt reduction package that was negotiated and make that work for them within the eurozone? Or do they want to take a different path? What they cannot do, I think, is just string this out endlessly with another round of conversations, discussions, negotiations. The world cannot wait for the eurozone to go through endless questions about this.

4.23pm: And here are the highlights from what some of the other G20 leaders have been saying at their end-of-summit press conferences.

• Nicolas Sarkozy, the French president, said France wanted to have a Robin Hood tax in place in the EU by the end of next year. He said "just putting the words financial transaction tax in a communique" would have been unthinkable not long ago. He said the Robin Hood tax was something talked about among NGOs and "never at the tables of heads of state". This was one development that showed "it's now a totally different world, it has progressed in a stupefying way."

He also said the "morally indispensable" tax was now technically possible. He said South Africa, Brazil and Argentina now supported the idea along with France, Germany, Spain, Eur Commision, African Union and secretary general of the UN, whereas once France was isolated in pushing for it. "France will fight for that tax to become a reality," he said.

At his press conference, he concentrated on issues like the Robin Hood tax and played down the failure to make more progress on economic issues. But he did say that the situation in Greece had changed considerably in recent days.

• He said that George Papandreou's decision not to tell fellow EU leaders about his plans to hold a referendum in Greece was "shocking".• He said France would not stand idly by if Iran threatened Israel. Barack Obama mentioned the threat posed by Iran's nuclear programme yesterday and Sarkozy also condemned the Iranians. "Iran's behavior and this obssessional desire to acquire nuclear military (capability) is in violation of all international rules, and France condemns firmly the lack of respect for these rules," he said. "If Israel's existence were threatened, France would not stand idly by." Next week a UN report is expected to offer intelligence pointing to possible military dimensions of Iran's nuclear program.• Silvio Berlusconi, the Italian prime minister, said his country was in a stronger economic position than France or the UK. "Italian restaurants and vacation spots are always full," he said. "Nobody has the sense the country is in a crisis." He said that he had turned down the offer of financial help from the IMF. But he had asked the IMF to monitor its economic reforms, he said.

• Angela Merkel, the German chancellor, said "hardly any" countries wanted to put more money into the European Financial Stability Facility. "There are hardly any countries that have said already they will cooperate with the EFSF," she said.• Barack Obama, the American president, said the G20 leaders had made progress at the summit to put to put "economic recoveries on a firmer footing". He also said that China's decision to allow more currency flexibility was "a critical step in boosting growth".• Dilma Rousseff, the Brazilian president, said Brazil would only provide financial assistance to Europe through the IMF. "I have no intention of contributing directly to the European [stabilization] fund," she said. "Why would I? They (Europeans) don't."

5.06pm: Last year I was speaking at a seminar with a senior Foreign Office official who was involved in Gordon Brown's G20 summit in London at 2009. He admitted that it was hard to assess whether events like this were really a success or not and that, beforehand, he decided he would use market reaction as the best guide. After the London G20 (where Gordon Brown unveiled a $1tr global economic rescue package) the markets went up. My Foreign Office official took that as a sign that summit had been a success, and generally that has remained a consensus view.

Applying the same test, the G20 summit at Cannes was a flop. Six weeks ago George Osborne said: "There is a sense from across the leading lights of the eurozone that time is running out for them. There is a clear deadline at the Cannes summit in six weeks time ... The eurozone has six weeks to resolve this political crisis." But Cannes has now finished and the G20 leaders have not done enough to restore confidence. That's why the markets are down. (See 3.22pm.)

That's the summit in a nutshell. There are other stories too, of course. I've got stacks on press releases on my desk from NGOs welcoming the progress that has been made on the Robin Hood tax. But on the big issue of the day, this summit has failed.

Sorry to end on such a gloomy note. I'm off home. Thanks for the comments.